Seven Things to Know About How Hurricanes Affect Wildlife

As Hurricane Irene made landfall on the East Coast this week, the news media was rightly focused on the many dangers to humans from such powerful storms. Due to the hurricane’s track, 2.5 million people were ordered to evacuate low-lying coastal communities, including, for the first time, parts of New York City.

But what happens to fish and wildlife during major storms? Here are a few of the ways species are affected and some things you can do to help them.

Wind Dislocation

Powerful winds from hurricanes and tropical storms can blow birds off course and push them hundreds of miles away from their home habitat. Last year, a North Carolina brown pelican was found on the roof of a night club in Halifax, Nova Scotia. The news often covers the appearance of rare species after a major storm. Sometimes younger or weaker birds become separated from their flock and many can take weeks to return home — if they can find the right foods on their way back.

During major storms, sea birds and waterfowl are most exposed. Songbirds and woodland birds, however, are specially adapted to hold on and ride things out. Their toes automatically tighten around their perch. This holds them in place during high winds or when they sleep. Woodpeckers and other cavity nesters will, barring the destruction of the tree itself, ride out storms in tree holes. Shorebirds often move to inland areas. In a unique effect of cyclonic hurricanes, the eye of the storm with its fast-moving walls of intense wind can form a massive “bird cage” holding birds inside the eye until the storm dissipates. It is often the eye of the storm that displaces birds, more than its strong winds.

Birds are not the only species affected by the winds. Sea mammals can be harmed too. While many can seek shelter in open water or in near shore shelter, some dolphins and manatees have actually been blown ashore during major storms.

Tree Loss

In 1992, Hurricane Andrew brought incredible wind velocities onshore and knocked down as many as 80% of the trees on several coastal Louisiana basins, such as the Atchafalaya. Tree loss duringHurricane Katrina in 2005 caused even more extensive damage. Loss of coastal forests and trees can be devastating to dependent wildlife species and migratory species. Many wildlife species have very specialized niches in these forests that are lost to heavy winds. Specific foods can be taken away too. High winds will often strip fruits, seeds and berries from bushes and trees.

Dune and Beach Loss

Storm surges, wave action, and winds can cause beach and dune erosion and that can have severe effects of species. Many wildlife species live in ecological niches in the sandy areas and dunes of coastal barrier island. In some cases the storm can cause a beach area to disappear. Sea turtle nests, for example, can be washed out, or a water surge, called a “wash over” can submerge these nests or tern and plover nesting areas.

Saltwater Intrusion

The sustained and powerful winds of a hurricane will cause salty ocean water to pile up and surge onshore. These “storm surges” can be huge. Hurricane Irene’s surges brought water levels that were as much as 8 feet above normal high tide and Katrina pushed a 30 foot high surge onto the coast. In addition to the physical damage this causes, the salt contained in sea water dramatically shifts the delicate balance of freshwater and brackish wetland areas. Creatures and vegetation that are less salt-tolerant will be harmed and many will not survive this influx of sea water. Marsh grasses, crabs, minnows, fish hatchlings, insects, and myriad creatures of freshwater and estuarine environments are harmed. The salt water intrusion in these some of these areas does not drain off very quickly and can even harm or kill off bottomland forests and other coastal trees.

Freshwater Flooding

The reverse is true too. The heavy rains generated by hurricanes will dump water in coastal area river basins (called watersheds) and this, in turn, can send vast amounts of fresh water surging downstream into coastal bays and estuaries. This upsets the delicate and finely tuned freshwater/salt water balance that can be so vital for the health of these ecosystems. In 1972, Hurricane Agnes sent such massive amounts of freshwater into the Chesapeake Bay. The normally brackish (partially salty) water was fresh for months placing great pressure on the species living there.

Turbidity

Heavy rainfall in upstream areas also washes soil, sediment and many pollutants into coastal and marine environments. After Hurricane Agnes, the turbidly or cloudiness of the water became so severe in the Chesapeake Bay that the native grasses growing on the bottom of Bay died off in huge quantities. These grasses provided critical habitat from crabs, fish spawning and many species. It took the Bay years to recover. Similarly, sediment can wash over coral reefs, blocking needed sunlight and even causing algae to grow.

Marine and Aquatic Species

Hurricane Irene, like other hurricanes, generated massive waves and violent action on the surface. When hurricane Andrew hit Louisiana the government estimated that more than 9 million fish were killed offshore. Similarly an assessment of the effect of that same storm on the Everglades Basin in Florida showed that 182 million fish were killed. Hurricane Katrina also had a huge effect on dolphin species. Many dolphins were hurt during the storm and were rescuded and underwest rehabiltation.

What Can You Do?

The forces of hurricanes, such as Irene, are so immense that they deserve tremendous respect. So the first thing you can do is to stay safe yourself. Heed public safety warmings, prepare your property by collecting and storing lose items outside, be prepared for power outages and use common sense. Following a storm, birders and wildlife enthusiasts can help by keeping their eyes peeled for unusual or rare species that turn up. It is useful for wildlife agencies to hear about rare appearances. Wildlife rescue organizations should be contacted if someone sees a creature that was injured in a storm. It always recommended to avoid trying to handle and injured animal on your own unless you have had specific training. If you usually feed birds at your home, the post storm calm is a good time to fill up those feeders. Your pals will probably be hungry and tired after waiting out the storm.